#include "std.h"
#include "otable.h"
#include "comm.h"
#include "hash.h"
#include "simul_efun.h"
#include "master.h"

/*
 * Object name hash table.  Object names are unique, so no special
 * problems - like stralloc.c.  For non-unique hashed names, we need
 * a better package (if we want to be able to get at them all) - we
 * cant move them to the head of the hash chain, for example.
 *
 * Note: if you change an object name, you must remove it and reenter it.
 */

static int otable_size;
static int otable_size_minus_one;

static object_t *find_obj_n(char *);

/*
 * Object hash function, ripped off from stralloc.c.
 */
#define ObjHash(s) whashstr(s, 40) & otable_size_minus_one

/*
 * hash table - list of pointers to heads of object chains.
 * Each object in chain has a pointer, next_hash, to the next object.
 */

static object_t **obj_table = 0;

void init_otable()
{
	int x, y;

	/* ensure that otable_size is a power of 2 */
	y = OTABLE_SIZE;
	for (otable_size = 1; otable_size < y; otable_size *= 2)
		;
	otable_size_minus_one = otable_size - 1;
	obj_table = CALLOCATE(otable_size, object_t *,
			TAG_OBJ_TBL, "init_otable");

	for (x = 0; x < otable_size; x++)
		obj_table[x] = 0;
}

/*
 * Looks for obj in table, moves it to head.
 */

static int obj_searches = 0, obj_probes = 0, objs_found = 0;

/* A global.  *shhhh* don't tell. */
static int h;

static object_t *find_obj_n(char * s)
{
	object_t *curr, *prev;

	h = ObjHash(s);
	curr = obj_table[h];
	prev = 0;

	obj_searches++;

	while (curr)
	{
		obj_probes++;
		if (!strcmp(curr->name, s))
		{ /* found it */
			if (prev)
			{ /* not at head of list */
				prev->next_hash = curr->next_hash;
				curr->next_hash = obj_table[h];
				obj_table[h] = curr;
			}
			objs_found++;
			return (curr); /* pointer to object */
		}
		prev = curr;
		curr = curr->next_hash;
	}

	return (0); /* not found */
}

/*
 * Add an object to the table - can't have duplicate names.
 * 
 * Exception: Precompiled objects have a dummy entry here, but it is
 * guaranteed to be behind the real entry if a real entry exists.
 */

static int objs_in_table = 0;

void enter_object_hash(object_t * ob)
{
	object_t *s;

	s = find_obj_n(ob->name); /* This sets h */

#ifdef DEBUG
	/* when these reload, the new copy comes in before the old goes out */
	if (s != master_ob && s != simul_efun_ob)
	{
#ifdef LPC_TO_C
		DEBUG_CHECK1(s && s != ob && (!(s->flags & O_COMPILED_PROGRAM)),
				"Duplicate object \"/%s\" in object hash table",
				ob->name);
#else
		DEBUG_CHECK1(s && s != ob,
				"Duplicate object \"/%s\" in object hash table",
				ob->name);
#endif
	}
#endif

	ob->next_hash = obj_table[h];
	obj_table[h] = ob;
	objs_in_table++;
	return;
}

/* for adding a precompiled entry (dynamic loading) since it is possible
 * that the real object exists.
 */
void enter_object_hash_at_end(object_t * ob)
{
	object_t *s;
	object_t **op;

	s = find_obj_n(ob->name); /* This sets h */

	ob->next_hash = 0;

	op = &obj_table[h];
	while (*op)
		op = &((*op)->next_hash);
	*op = ob;
	objs_in_table++;
	return;
}

/*
 * Remove an object from the table - generally called when it
 * is removed from the next_all list - i.e. in destruct.
 */

void remove_object_hash(object_t * ob)
{
	object_t *s;

	s = find_obj_n(ob->name); /* this sets h, and cycles the ob to the front */

	DEBUG_CHECK1(s != ob, "Remove object \"/%s\": found a different object!",
			ob->name);

	obj_table[h] = ob->next_hash;
	ob->next_hash = 0;
	objs_in_table--;
	return;
}

#ifdef LPC_TO_C
void remove_precompiled_hashes(char * name)
{
	int h = ObjHash(name);
	object_t **p;
	object_t *curr;

	p = &obj_table[h];

	while (*p)
	{
		if (((*p)->flags & O_COMPILED_PROGRAM) && !strcmp((*p)->name, name))
		{
			curr = *p;
			FREE(curr->name);
			FREE(curr);
			(*p) = (*p)->next_hash;
		}
		else
		p = &((*p)->next_hash);
	}
}
#endif

/*
 * Lookup an object in the hash table; if it isn't there, return null.
 * This is only different to find_object_n in that it collects different
 * stats; more finds are actually done than the user ever asks for.
 */

static int user_obj_lookups = 0, user_obj_found = 0;

object_t *lookup_object_hash(char * s)
{
	object_t *ob = find_obj_n(s);

	user_obj_lookups++;
	if (ob)
		user_obj_found++;
	return (ob);
}

/*
 * Print stats, returns the total size of the object table.  All objects
 * are in table, so their size is included as well.
 */

static char sbuf[100];

int show_otable_status(outbuffer_t * out, int verbose)
{
	int starts;

	if (verbose == 1)
	{
		outbuf_add(out, "Object name hash table status:\n");
		outbuf_add(out, "------------------------------\n");
		sprintf(sbuf, "%10.2f", objs_in_table / (float) OTABLE_SIZE);
		outbuf_addv(out, "Average hash chain length:       %s\n", sbuf);
		sprintf(sbuf, "%10.2f", (float) obj_probes / obj_searches);
		outbuf_addv(out, "Average search length:           %s\n", sbuf);
		outbuf_addv(out, "Internal lookups (succeeded):    %lu (%lu)\n",
		        obj_searches - user_obj_lookups, objs_found - user_obj_found);
		outbuf_addv(out, "External lookups (succeeded):    %lu (%lu)\n",
		        user_obj_lookups, user_obj_found);
	}
	starts = (int) OTABLE_SIZE * sizeof(object_t *)
	        + objs_in_table * sizeof(object_t);

	if (!verbose)
	{
		outbuf_addv(out, "Obj table overhead:\t\t%8d %8d\n",
		        OTABLE_SIZE * sizeof(object_t *), starts);
	}
	return starts;
}
